A transducer assembly for measurement of downhole temperature and pressure includes a crystal resonator responsive to temperature and a pair of temperature sensors such as thermocouples or RTDs. Rotation of the handles 180 degrees exposes the compound brush assembly for use. The measured potential-derivative is compared with a preferred anode potential-derivative of an anode charge curve or an anode discharge curve, and with a preferred cathode potential-derivative of a cathode charge curve or a cathode discharge charge curve. In a further embodiment, the hook further includes a logo of a company.